Automobiles are equipped with air bags to prevent injuries to passengers when crashes, rollovers, and other mishaps occur. Accelerometers within an auto continuously measure acceleration or deceleration of the auto and continuously report the acceleration or deceleration to an on-board computer, such as an electronic control unit (ECU). When deceleration reaches a certain magnitude, as it does in the early moments of a crash, the on-board computer signals one or more airbags to deploy. The airbag then inflates and an instant cushion of air shields a person in the auto from some of the forces associated with the deceleration.
There are problems with airbags, however. In order to very quickly inflate to a level that will protect a person, inflation of the airbag creates a great force on the person receiving the supposed benefits of the airbag. This force is great enough to kill children or even small adults. In many cases, the force may be unnecessary, particularly if the airbag does not need to be inflated. These cases may occur if the load on the seat is a rear-facing child seat, which may adequately protect the child by itself, without the need for an airbag. In other instances, there may be no load on the seat, or the load on the seat may be inanimate or non-human, such as groceries, books, or bags. In these instances, there is no need to deploy the airbag. In other instances, it may be useful to note the weight or mass of the load, to determine whether the seat is occupied by a person requiring an airbag. It may also be useful to determine the shape of the load, and whether the load is shaped more like a box or a parcel or more like the seat portion of a human.
There are a number of problems with designing a seat with sensors for detecting a load, such as a person, on a seat. The seats of interest are primarily the front seats, concerned with airbags from the front portion of the passenger compartment that may impact the front-seat passengers. Seats in different automobiles are used for different purposes and have different sizes. It will be very difficult to have a single “standard” seat for autos or passenger cars. Auto seats come in many sizes and configurations from different manufacturers and even among different models from the same manufacturer. A driver's seat in an auto will almost always have an adult or a young adult, and thus may have a heavy load. A front passenger seat in an auto may seat an adult, a child, a child or infant seat that faces rearward or forward, or a child booster seat that faces forward (for older children). Thus, the passenger seat may have a lighter load at times. The front passenger seat may also have only an inanimate object on the seat, not requiring deployment of the airbag. Different seats from different manufacturers may have different configurations and may require different hardware and software solutions.
Attempts have been made to classify seat occupants by using the weight or mass alone. U.S. Pat. No. 6,040,532 determines the weight of a seat occupant by detecting variation in load from detectors under the seat. This method and apparatus will detect a mass, but will not indicate whether the mass is shaped like a human or a package. U.S. Pat. No. 6,353,394 uses sensors under the seat to determine the mass of an object in the seat. This method of classifying may yield a weight or mass, but again does not indicate whether the shape of the object is more like a human being or like a non-human object. U.S. Pat. Appl. Publ. 2003/0051564 A1 also uses weight sensors or load cells under the seat to determine a mass of the load on the seat. The apparatus and method in this publication also will not determine the shape of the load to help determine whether it is appropriate to deploy the airbag.
What is needed is a method and apparatus to better classify the occupant or load in a seat in order to determine whether it is appropriate to deploy an airbag. The present invention is aimed at overcoming these deficiencies in the prior art.